The impact of age and gender with respect to general joint laxity, shoulder joint laxity and rotation

Microsoft Word - Annas Kappa 15 mars.docKarolinska Institutet, Stockholm, Sweden
shoulder joint laxity and rotation
- A study of 9, 12 and 15 year old students
Anna Jansson
Stockholm 2005 Supervisor: Suzanne Werner, RPT, PhD Co-supervisors: Tönu Saartok, MD, PhD Per Renström, MD, PhD
I would like to show my enormous gratitude to all the young students participating in these studies, who made this thesis possible.
All previously published papers were reproduced with permission from the publisher. Published and printed by Karolinska University Press Box 200, SE-171 77 Stockholm, Sweden © Anna Jansson, 2005 ISBN 91-7140-323-X
Abstract The overall aim of this thesis was to study the natural development of general joint laxity, shoulder joint laxity and shoulder joint rotation in young students, and compare these to age-matched competitive swimmers to detect possible discrepancies between these groups. A further aim was to evaluate the clinical examination techniques used whether they correlate to each other in search of better understanding and interpretation of achieved measurement results. Material Forty-eight randomly selected schools participated in this Swedish nation-wide research study (‘The School project 2001’) with a total of 1846 students aged 9-15 included. Data concerning these subjects are reported in study I-III. An additional study group of 120 competitive swimmers, aged 9 and 12 year, were included and compared to the previously described group. Data concerning these subjects are reported in study III. Out of the original 1846 students, 156 of ages 12 and 15 years participated in a follow-up examination in 2004. A geographic selection was made for practical reasons. Data concerning these subjects are reported in study IV. Methods General joint laxity was scored according to Beighton. Anterior, posterior and inferior shoulder joint laxity was assessed with the drawer test and the sulcus sign, respectively. Shoulder joint rotation was measured with a Myrin™ OB goniometer. One and the same examiner (AJ) performed all tests in the same standardized manner both in 2001 and 2004. Results General joint laxity: A cut-off point scheme was designed by Jansson et al and differed with respect to age and gender in 2001 and was confirmed in 2004. Girls had a higher degree of general joint laxity compared to boys and male competitive swimmers had a higher degree compared to their references. Nine year old female competitive swimmers had a lower degree of general joint laxity compared to their references. The individual differences between 2001 and 2004 showed only minor changes. Shoulder joint laxity: Fifteen year old boys had a lower anterior and posterior laxity compared to girls. No significant difference was seen between competitive swimmers and their references. The individual change, over three years, showed a decrease in anterior laxity in boys. Shoulder joint rotation: Girls had higher external rotation compared to boys at the age of 12 and 15 years. Shoulder joint rotation was noted as lower in all competitive swimmers at the age of 12 years compared to their reference group. Fifteen year old students had decreased their shoulder rotation at follow-up. Conclusion Based on this study of Swedish students and competitive swimmers, the degree of general joint laxity and shoulder joint rotation is specific in terms of age, gender and sports participation. Shoulder joint laxity, however, was found to be only age and gender specific and were not associated with general joint laxity. The scheme for cut-off points regarding general joint laxity was gender and age dependent and confirmed at the three year follow-up. There were only minor changes in general joint laxity and shoulder joint laxity at follow-up, but a majority of students had a decrease in shoulder joint rotation over the same time period.
List of publications This thesis is based on the following papers, which will be referred to in the text by their Roman numbers (studies I-IV) I. General joint laxity in 1845 Swedish school children of different
ages - age and gender specific distributions.
Anna Jansson, Tönu Saartok, Suzanne Werner, Per Renström Acta Paediatrica 93 1202-1206, 2004
II. Is general joint laxity an indicator of excessive laxity of the shoulder joint in children?
Anna Jansson, Tönu Saartok, Per Renström , Suzanne Werner Submitted for publication
III. Evaluation of hypermobility, shoulder laxity and mobility in competitive swimmers during growth and in normal controls.
Anna Jansson, Tönu Saartok, Suzanne Werner, Per Renström
Scandinavian Journal of Medicine and Science in Sports. Online publication date: 27-Oct-2004
IV. The impact of age and gender with respect to general joint laxity, shoulder joint laxity and rotation in adolescents – a three year follow-up. Anna Jansson, Per Renström, Suzanne Werner Manuscript
We acknowledge with thanks Acta Paediatrica and Scandinavian Journal of Medicine and Science in Sports to which the copyright to the original papers (I and III) belong. The journals have given their permission for the publication of reprints in this thesis.
Table of Contents Abbreviations 1 Definitions 2 Introduction 3
SShhoouullddeerr aannaattoommyy 44 BBoonnyy ssttrruuccttuurreess 44 LLaabbrruumm 55 CCaappssuulloolliiggaammeennttoouuss ssttrruuccttuurreess 55 GGlleennoohhuummeerraall mmuusscclleess 55 RRaannggee ooff mmoottiioonn 66 SShhoouullddeerr jjooiinntt llaaxxiittyy//ssttaabbiilliittyy 77 HHyyppeerrmmoobbiilliittyy 88 TTeesstt ooff sshhoouullddeerr jjooiinntt llaaxxiittyy 99 TThhee uunnssttaabbllee sshhoouullddeerr jjooiinntt 99 TThhee ggrroowwiinngg iinnddiivviidduuaall 99 GGeenneettiiccss aanndd eennvviirroonnmmeennttaall ffaaccttoorrss 1100 TThhee ccoommppeettiittiivvee sswwiimmmmeerr 1100
Aim of thesis 12 Material & Methods 13
SSuubbjjeeccttss 1133 GGeenneerraall jjooiinntt llaaxxiittyy 1144 SShhoouullddeerr jjooiinntt llaaxxiittyy 1144
DDrraawweerr tteesstt 1144 SSuullccuuss ssiiggnn 1155
SShhoouullddeerr jjooiinntt rroottaattiioonn 1155 TTeesstt ffoorr iinnttrraa--rreelliiaabbiilliittyy 1166
TTeesstt ffoorr iinntteerr--rreelliiaabbiilliittyy 1166 SSttaattiissttiiccss 1166 EEtthhiiccaall ccoonnssiiddeerraattiioonn 1166
Results 17 GGeenneerraall jjooiinntt llaaxxiittyy 1177 SShhoouullddeerr jjooiinntt llaaxxiittyy 1199 SShhoouullddeerr jjooiinntt rroottaattiioonn 2200 CCoorrrreellaattiioonn ooff eexxaammiinnaattiioonn tteecchhnniiqquueess 2222 IInnttrraa--rreelliiaabbiilliittyy 2233 IInntteerr--rreelliiaabbiilliittyy 2244 AAggrreeeemmeenntt iinn--bbeettwweeeenn 22000011 aanndd 22000044 2255
Discussion 27
Acknowledgement 35 References 38 Original papers I, II, III & IV
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Abbreviations AMBRI Atraumatic, multidirectional, bilateral, rehabilitation, inferior
capsular shift ANOVA Analysis of variance AROM Active range of motion C.I. Confidence Interval DZ twins Dizygotic twins Fisher LSD Fisher least significant difference method IGHL Inferior glenohumeral ligament ICC Intraclass-correlation coefficient MCP V Metacarpal phalangeal five (fifth finger) MGHL Middle glenohumeral ligament MZ twins Monozygotic twins ROM Range of motion SD Standard deviation SGHL Superior glenohumeral ligament TROR Total range of rotation TUBS Traumatic, unidirectional instability, Bankart lesion, surgery
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Definitions Laxity The physiological translation during a passive motion within the joint without the influence of pain.63 Instability The subjective experience by the individual with respect to his/her perceived joint stability, which presupposes an excessive joint play with the influence of pain during an active motion.63 TUBS The ‘TUBS’ group defines individuals who have a traumatic aetiology of instability. The problem is usually unilateral, patients often have a Bankart lesion, and they generally require a surgical solution of the problem.75 AMBRI The ‘AMBRI’ group includes individuals with atraumatic aetiology. These patients usually have multidirectional instability, bilateral symptoms, and often respond to conservative rehabilitation program. In the event of failure in rehabilitation, an inferior capsular shift is the choice of surgical procedure.75 Multidirectional instability An excessive inferior instability in combination with an additional direction of instability (anterior/posterior).61 Hypermobility A hypermobile joint is one whose range of movements exceeds the norm for that individual, taking into consideration age, sex, and ethnic background.30
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Introduction There is a report suggesting documentation of hypermobility as early as the mid 1600. This statement by Dequeker 18 would, if correct, change the common belief that Kirk et al were among the first to describe this condition in 1967.48 In the painting “The Three Graces” by Peter Paul Rubens, females with a clearly manifest S-shape scoliosis, positive Trendelenburg, hyperextension of the distal interphalangeal and metacarpophalangeal joints are subjects of interest (figure 1). Further investigations by Dequeker reveal that the three females are sisters and therefore likely to have the same genetic traits. To conclude this rather unusual investigation the author suggests the working diagnosis of the three graces most likely to be ‘familial benign hypermobility’. These rheumatic features could, however, be explained by so called “contrapposto postures” common in the Renaissance period, ‘to give the impression of vigorous muscular characters capable of performing great tasks’.38 Who actually has the correct opinion one can speculate, but it would not be fair to deprive Kirk et al of being pioneers in strictly scientifically describe this interesting field of hypermobile features. Figure 1: Three Graces by Peter Paul Rubens 1638-1640 (Ann Rheum Dis 2001;60:894).
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In epidemiological studies of sport injuries there have been discussions about a possible correlation between the risk of overuse injuries and the individual joint stability.39, 51, 78 In gymnastics, it seems favourable to have an increased joint mobility and being ‘abnormally’ flexible for optimal performance.26 In competitive swimming, which may be regarded as a bilaterally repetitive overhead sport, a high percentage of the swimmers seems to have increased shoulder joint mobility. The risk of getting symptomatic shoulder joint laxity, often referred to as ‘swimmer’s shoulder’, seems to increase with years of participation in competitive swimming.4, 46, 59 A crucial question in this regard is whether repetitive activities over years of participation may lead to ‘tissue fatigue’ and increased laxity and in some cases eventually to pathological hyperlaxity. Alternatively, if individuals with a ‘favourable’ joint laxity may have benefits in certain sports, thereby choosing to remain in that sport and possibly leading to future success. The early sport success due to hypermobility may, in the long run, lead to instability.
SShhoouullddeerr jjooiinntt aannaattoommyy
In any joint, the architecture of bony structures, the tension and quality of the stabilizing soft tissue (e.g. ligaments and capsule) and the surrounding skeletal muscle and tendons all contribute to functional stability. The bony structures, the labrum, glenohumeral ligaments, joint capsule and the negative joint pressure all contribute to static stability in the shoulder. The rotator cuff muscles, biceps muscle and deltoid muscle all constitute dynamic restraints. This collaboration allows large movements of the joint, but also enhances the risk of getting excessive shoulder joint laxity, which may lead to instability problems. BBoonnyy ssttrruuccttuurreess The glenohumeral joint is a shallow form of ball joint, with a relatively big head (humeral head) placed in a shallow socket (the glenoid). The adult glenoid cavity is less than 10 mm deep, shaped somewhat like a 20 by 30 mm comma and may be either anteverted or, most commonly (75%), retroverted in relation to the body of scapulae. Also, it is described having an inferior-lateral tilt of about 15°. The adult humeral head has a diameter of about 40-50 mm, thereby being ‘oversized’ in relation to the glenoid. Since only 25-35% of the humeral head is in contact by the glenoid the bony contribution to the stability of the glenohumeral joint is limited.20
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LLaabbrruumm The labrum acts primarily as a deepening and stabilizing structure to the glenoid cavity, adding an additional 2-3 mm of depth both anteriorly and posteriorly. It consists of dense fibrous tissue and its function resembles that of the meniscus in the knee.20 CCaappssuulloolliiggaammeennttoouuss ssttrruuccttuurreess The capsule of the shoulder joint consists of a variably thick layer of collagen, where the discrete variable thickenings constitute the three glenohumeral ligaments.20, 79 The superior glenohumeral ligament (SGHL) is regarded as a static stabilizer in anterior- posterior direction, but has also been shown to be the primary restraining component in the inferior direction. 20, 79 The middle glenohumeral ligament (MGHL) is stabilizing the inferior translation during adduction and external rotation and restricts external rotation during simultaneous adduction. 20, 79
Figure 2: The shoulder joint anatomy (Peterson,
Renström: Sports Injuries. Their Prevention and
Treatment, Dunitz, London, p: 114, Nov 2000, with
permission)
The IGHL consists of an anterior and posterior band and act as restraining components of the humeral head during rapid anterior displacement. The IGHL is the primary static anterior and posterior stabilizing component but also offers support in the inferior direction during abduction. In case of injury to the anterior part of the (IGHL) the MGHL steps in and gives support in the anterior direction. 20, 79 GGlleennoohhuummeerraall mmuusscclleess The largest and perhaps most important muscle in the glenohumeral region is the deltoid muscle with its three major parts. They originate from the lateral one-third of the clavicle, from the acromion and from the spine of the scapulae and inserts on to the deltoid tubercle of the humerus. The middle part is involved in all sorts of elevation of the arm. Scapular elevation and abduction in the coronal plane is mainly performed by the anterior and middle part of the deltoid.20, 42
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The rotator cuff consists of four muscles, namely suprapsinatus, infraspinatus, teres minor and subscapularis. Together they surround the glenohumeral joint, humeral head, and the joint capsule. The supraspinatus muscle originates from the supraspinatus fossa of the scapula and inserts into the greater tuberosity. It is active during any sort of elevation but has the maximum effort at about 30° of abduction. The supraspinatus plays an important stabilizing role in the shoulder joint. Together with the infraspinatus and subscapularis muscles, the suprapsinatus provides a downward force on the humeral head to resist the upward force originated from the large deltoid during elevation of the arm.20, 42 The infraspinatus muscle is regarded to be the ‘second most active’ rotator cuff muscle. It originates from the infraspinatus fossa of the scapulae and inserts on the great tuberosity. It acts mainly as an external rotator but also as a depressor of the humeral head. The infraspinatus also stabilizes the humeral head against posterior subluxation during internal rotation by creating a forward force. The teres minor muscle originates from the middle portion of the lateral border of the scapulae and the fascia of the infraspinatus and inserts into the greater tuberosity of the humerus. It acts as an external rotator in controlling for anterior stability.20, 42 The subscapularis muscle originates from the subscapularis fossa, which covers most parts of the anterior surface of the scapulae, and inserts into the lesser tuberosity on the humerus. It functions as an internal rotator and stabilizer to anterior subluxation and depresses the humeral head during elevation of the arm. The teres major muscle originates from the posterior surface of the scapulae and inserts together with latissimus dorsi into the lesser tuberosity of the humerus. The teres major mainly function as an internal rotator, adductor and in extension of the arm.20, 42 The coracobrachialis muscle originates from the coracoid process together with the short head of the biceps muscle and inserts onto the humerus on the anteromedial surface in the midportion. The coracobrachialis functions as a flexor and adductor.20, 42 The long head of the biceps muscle originates from the superior labrum of the glenoid, overrides the humeral, continues into the biceps groove, and inserts at the lower arm. This two-joint muscle acts as a depressor of the humeral head and a flexor of the glenohumeral joint.20, 42
RRaannggee ooff mmoottiioonn The shoulder joint has greater mobility than most other joints and can be moved in several planes. The greatest motion is often achieved by a compounded movement of the shoulder joint.
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For example, in order to perform a shoulder joint flexion one needs to include a slight external rotation and abduction to achieve maximal flexion. Normal range of motion (ROM) of the shoulder joint has been described by Boone and Azen and is based on 109 male subjects between the ages of 1.6 years and 45 years.11 For details, see Table 1. Specific sport participation has been reported to cause changes in the shoulder mobility pattern in young athletes. Ellenbecker at al found a decrease in internal rotation in the dominant arm in tennis players.23 An increase in external rotation is often seen in the dominant arm in baseball players and competitive swimmers often display an increased external rotation together with a increased internal rotation.5, 55 Regardless of an increase or decrease in rotation, one need to take these findings into consideration in the development of rehabilitation and preventative flexibility/range of motion programs.
Table 1: Active range of motion (AROM) of the shoulder joint in male subjects according to Boone
and Azen. Degree (°) of motion is displayed in mean values (M) and standard deviation (SD).11 AROM
M SD Flexion 167° 4.7° Extension 62° 9.5° External rotation (in 90º abd) 104° 8.5° Internal rotation (in 90º abd) 69° 4.6° Abduction 184° 7.0°
SShhoouullddeerr jjooiinntt llaaxxiittyy//ssttaabbiilliittyy Laxity describes the physiological translation during a passive motion within the joint without the influence of pain.63 This is a normal feature of the soft tissue surrounding the shoulder joint and is required for normal glenohumeral motion. The degree of laxity differs between individuals and is suggested to be affected by factors such as age and gender.12, 24, 57 Instability, on the other hand, describes the subjective experience of the individual with respect to their perceived joint stability and presupposes an excessive joint play with the influence of pain during an active motion.63 A spectrum of instability exists and represents increasing degrees of injury to either the dynamic or static stabilizing components of the shoulder joint. Instability can be classified according to direction (anterior, posterior, inferior), degree (subluxation, dislocation), aetiology (traumatic, atraumatic and ‘overuse’) and finally to interval of time (acute, relapse and inveterate).1
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A well-known concept describing the spectrum of instability is TUBS (traumatic aetiology, unidirectional instability, Bankart lesion, surgery required) and AMBRI (atraumatic, multidirectional instability (possibility), bilateral symptoms, rehabilitation (conservative), inferior capsular shift (if surgery required). This classification was introduced by Tomas and Matsen in 1989.75 The idea of an instability classification based on aetiology may be misleading in young athletes involved in overhead sports according to Pollock and Flatow. They state that ‘These patients demonstrate that overlap between etiology categories rather than two or three discrete groups, may exist in a clinical population’.67 A multidirectional instability describes an excessive inferior instability in combination with an additional direction of instability (anterior/posterior).61 HHyyppeerrmmoobbiilliittyy Wood stated in 1971that ‘hypermobility merely represents the upper end of a Gaussian distribution of the ‘normal’ joint range of motion’. 80 This statement has been challenged by the notion that the difference in hypermobility, especially seen in the clinic, may be so called abnormal.30 Two types of hypermobility are nowadays described in the literature. The first is occurring in people whose joints are just like everyone else's but which have the capacity to move more than most people's joints, so called benign hypermobility syndrome.29 This has been recognized during the last decades. Secondly, a more marked form has features that suggest that it may be part of an inherited connective tissue disorder 29. ‘A hypermobile joint is one whose range of movements exceeds the norm for that individual, taking into consideration age, sex, and ethnic background’. 30 Joint hypermobility was described by Kirk et al in 1967 who stated that this phenomenon was a combination of musculoskeletal disorders and joint laxity without other rheumatic diseases.48 Previous authors have shown that hypermobility can either be inherent in a person’s genes and/or can be acquired.16, 30, 50 Age, gender and ethnic background are the three most discussed factors that might have an impact on the degree of joint mobility. Normal joint range can also be changed into hypermobility by hard training such as for example ballet dancers.28, 30, 32 In 1964, Carter & Wilkinson were the first to design a score evaluating general hypermobility e.g. general joint laxity.15 In 1973, Beighton et al modified the score, which now appears to be the most used score to estimate general joint laxity.9
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The score cannot however be relied upon to identify pauci-articular hypermobility and authors suggest using the score together with a careful examination of contiguous joints.30, 37 The additional joints of interest are the tempomandibular joint, cervical spine, shoulder joint, wrist,…